This invention relates to a chair and its support, and more particularly, to a chair and support designed to provide in use a degree of controlled "yield" for the particular purposes described below.
Studies in the field of ergonomics have shown that by encouraging subtle and unconscious use of muscle groups ordinarily at rest, the body may be energized in a way which manifests itself in longer, more comfortable and more efficient work spans. In one of its aspects, the present invention provides a resilient seat support, exploiting elastomeric and other spring elements as well as the flexibility and resilience of other parts of the chair, to provide a controlled yield in the fore and aft, as well as lateral and oblique directions. In other words, when the occupant of a chair in accordance with the invention chooses to lean to the rear, a tilting action, conventional in many chairs, takes place. If the occupant also leans slightly to the left or to the right, or if the occupant while sitting upright reaches to the left or right, the chair shifts slightly to a limited and desirable extent, following the body and inducing the occupant to use a series of different muscle groups to counteract the tilt.
It has been suggested that these desired body movements be facilitated by the design of a chair. See, for example, U.S. Pat. No. 4,500,137, issued Feb. 19, 1985, to Laurence E. Morehouse. The chair shown in that patent, by its shape, seeks to motivate and accommodate motion by the occupant. The present invention likewise seeks to accommodate beneficial motion, but uses a different approach.